The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 2000
Filed:
Dec. 04, 1997
Kenzo Shodo, Kyoto, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
An optical pickup that does not require adjustment of the input/output characteristic of its automatic power control circuit to keep its signal output level at a specific level is proposed. In an optical pickup comprising a light-reception photodiode for converting light reflected from a disk into a current signal, a current-to-voltage converter for converting the current signal outputted from the light-reception photodiode into a voltage signal, a monitoring photodiode for converting part of the light emitted from a semiconductor laser device into a current signal, and an automatic power control circuit for controlling the semiconductor laser device by feedback based on the current signal outputted from the monitoring photodiode, a pair of photodiodes that convert a light signal into a current signal with equal efficiency are used as the light-reception and monitoring photodiodes.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile